Nondestructive examination (NDE) may be used to evaluate properties of composite structures. For instance, NDE such as ultrasonic testing may reveal internal structural inconsistencies such as voids, wrinkles, cracks and delaminations.
However, ultrasonic testing does not reveal internal strains within composite structures. Other techniques may determine strains at the surface or bulk of composite structures, but not within the composite structures.
It would be desirable to nondestructively determine strains within composite structures.